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Fig. 1
Wnt8a overexpression induces liver cells in the endoderm posterior to the liver. Embryos obtained from outcrossing Tg(hs:wnt8a) zebrafish were heat-shocked at 26 (A,B) or 22 (C-F) hpf, and processed for whole-mount immunostaining. (A,B) The Tg(fabp10:dsRed,ela3l:EGFP);Tg(ptf1a:eGFP);Tg(ins:dsRed) line was used to reveal hepatocytes (red), pancreatic acinar cells (green) and pancreatic β cells (red); mAb 2F11 staining reveals the hepatopancreatic duct (blue). The bracket marks the region with ectopic hepatocytes (n=7 out of 7). (C-F) Anti-Prox1 and anti-Pdx1 staining at 30 hpf (D; n=4 out of 4) reveals that Wnt8a overexpression induced Prox1 expression in endodermal cells located at the level of the second somite (S2) and blocked Pdx1 expression in these cells (the Pdx1 staining in the somites is due to non-reactivity as pdx1 is not expressed there). At 40 hpf, the endoderm posterior to the liver-forming region expressed Prox1 but not Pdx1 (F, bracket, n=4 out of 4). Dotted lines outline the dorsal pancreas, and S1-S3 represent the first, second and third somite, respectively. Ventral views, anterior up. Scale bar: 50 μm.